“I think it would be a bad choice,” Mr. Trump said on ABC’s “Good Morning America” when asked about the prospect of Sen. Ted Cruz of Texas tapping Mrs. Fiorina as a running mate.

“I mean, Carly did not resonate. Not because she’s a woman, but Carly did not resonate at all with people,” Mr. Trump said. “She had one good debate — not against me — she had the debate on the other stage, if you remember.”

“She had the one good debate, she went up and then she dropped like a rock, and she never resonated with the people,” he said. “So I mean, Carly’s not going to do the trick.”

“But she never resonated, she didn’t do well, she was very low in the polls and by the end she was an insignificant player,” he said. “So if he wants to bring Carly back, that’s OK. But it’s not the right person.”

Mrs. Fiorina’s camp confirmed in recent days that the Cruz campaign is vetting the businesswoman as part of the vice presidential selection process. Mr. Cruz has confirmed that his campaign has started the process of vetting potential vice presidential candidates but has not offered specific names.

Mrs. Fiorina endorsed Mr. Cruz for president last month. She dropped out of the race in February after disappointing finishes in Iowa and New Hampshire.

Mr. Trump said that at any rate, Mr. Cruz was wasting his time because the Texas Republican is not going to be the GOP nominee.

Mrs. Fiorina did deliver one of the more memorable lines of the GOP debates after Mr. Trump was quoted in a Rolling Stone article as saying “Look at that face!” and “Would anyone vote for that?” in reference to her. Mr. Trump later said he was referring to her persona and not her looks.

At a September debate, when Mrs. Fiorina was on the main stage, she said, to applause: “I think women all over this country heard very clearly what Mr. Trump said.”

“I think she’s got a beautiful face, and I think she’s a beautiful woman,” Mr. Trump said in response.